This proposal addresses the need for a scanning electron microscope (SEM) with Gatan 3View to serve the research community of the New York University Langone Medical Center (NYULMC), and primarily a group of five NIH-funded investigators with compelling need for this new level of instrumentation. The requested SEM will be hosted by the Microscopy Core Facility of NYULMC. The Core currently serves researchers with a wide variety of imaging needs by providing state-of-the-art microscopy and computer image analysis services ranging from macro-light microscopy to high-resolution single-molecule electron microscopy. The requested SEM is a multi-functional instrument that allows for ultrastructural 3D reconstruction, conjugated light-electron array tomography, and correlative light and electron microscopy. This SEM will be used for rapidly screening serial sections prepared for transmission electron microscopy and, together with an integrated microtome inside the specimen chamber, for producing automated high resolution 3D reconstructions representing large volumes of cells or tissues. Correlation between light and electron microscopy will be possible by use of the Shuttle and Find software. Projects from 5 major NIH-funded investigators are described that are in need of these various advanced SEM imaging techniques. These projects address fundamental mechanisms of cardiac arrhythmias, stem cell development, HIV pathogenesis, and neurodegenerative diseases. The major users combined have an estimated need of 80% of instrument time. The remaining time will be available to any of the over 100 users of the Microscopy Core Facility. This facility was established by the PI ten years ago and is financially supported by the institution's Office of Collaborative Science. The facility has a robust administrative structure and a strong network of scientific collaborations. The Microscopy Core has five full-time staff members assisting users in every step, from experimental design to image analysis to presentation. Overall, the versatility of the requested SEM, the variety of images that can be recorded, the diversity of samples that can be accommodated, and the wide range of imaging resolutions that can be obtained will greatly enhance the scope of electron microscopy provided for the research community at NYULMC.